Stereocontrolled total syntheses of (+)-penicibilaenes A and B were accomplished through three key steps: (1) Pd-catalyzed enantioselective desymmetrization to afford a pivotal chiral intermediate having an all-carbon quaternary stereogenic center, (2) ring-closing metathesis to form the bicyclo3.3.1nonane core, and (3) intramolecular nitrile oxide 3 + 2 cycloaddition to assemble the tricyclo6.3.1.01,5dodecane skeleton. Enantioselective desymmetrization delivered a highly functionalized cyclohexene, which provided access to (+)-penicibilaenes A and B.
Iwanaga et al. (Mon,) studied this question.